Method for measurement of ionized calcium
The present invention relates to a method for quantitatively determining ionized calcium in a sample by using a phospholipase, which comprises carrying out an enzyme reaction with the phospholipase in a buffer comprising a nitrogen heterocycle-binding sulfonic acid having a pK ranging 6.6 to 7.6 or a salt thereof.According to the method of the invention, the amount of ionized calcium in a sample, such as serum, can be accurately determined.
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Claims
1. A method for quantitatively determining ionized calcium, which comprises the steps of:
- selecting a sample;
- carrying out an enzyme reaction with a phospholipase in a buffer comprising a nitrogen heterocycle-binding sulfonic acid selected from the group consisting of N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid, 3-(N-morpholino) propanesulfonic acid, 1,2-N, N'-bis(N",N'"-di(2-sulfoethyl)piperazino)ethane, and a salt thereof;
- quantitatively determining a reaction product of said enzyme reaction; and
- correlating an amount of said reaction product with an amount of ionized calcium in said sample.
2. The method of claim 1 wherein the nitrogen heterocycle-binding sulfonic acid is N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid, 3-(N-morpholino) propanesulfonic acid, or a salt thereof.
Referenced Cited
Patent History
Patent number: 5840512
Type: Grant
Filed: Apr 3, 1996
Date of Patent: Nov 24, 1998
Assignee: Kyowa Medex Co., Ltd. (Tokyo)
Inventors: Toshio Tadano (Shizuoka), Akira Miike (Shizuoka), Norihiko Kayahara (Kanagawa), Jun Umemoto (Hyogo)
Primary Examiner: Louise Leary
Law Firm: Fitzpatrick, Cella, Harper & Scinto
Application Number: 8/553,512
Type: Grant
Filed: Apr 3, 1996
Date of Patent: Nov 24, 1998
Assignee: Kyowa Medex Co., Ltd. (Tokyo)
Inventors: Toshio Tadano (Shizuoka), Akira Miike (Shizuoka), Norihiko Kayahara (Kanagawa), Jun Umemoto (Hyogo)
Primary Examiner: Louise Leary
Law Firm: Fitzpatrick, Cella, Harper & Scinto
Application Number: 8/553,512
Classifications
Current U.S. Class:
Involving Hydrolase (435/18);
Measuring Or Testing Process Involving Enzymes Or Micro-organisms; Composition Or Test Strip Therefore; Processes Of Forming Such Composition Or Test Strip (435/4);
Standards, Controls, Materials (e.g., Validation Studies, Buffer Systems, Etc.) (435/967);
Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra (436/79);
Present In Biological Fluids (e.g., Blood, Urine, Etc.) (436/74);
424/941;
424/946;
Piperazines (i.e., Fully Hydrogenated 1,4-diazines) (544/358);
Nitrogen And Hydrogen Containing (252/374)
International Classification: C12Q 134; C12Q 100; H01L 21302;
International Classification: C12Q 134; C12Q 100; H01L 21302;